The Phanerozoic Record of Global Sea-Level Change

Abstract

We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new
sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 ± 50 meters during the Cretaceous,
implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations,
reflecting ice-volume change on the 104- to 106-year scale, but a link between oxygen isotope and sea level on the 107-year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level
change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic
sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic
ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large
Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).

Full text

The Phanerozoic Record of Global
Sea-Level Change
Kenneth G. Miller,
1
*
Michelle A. Kominz,
2
James V. Browning,
1
James D. Wright,
1
Gregory S. Mountain,
1,3
Miriam E. Katz,
1
Peter J. Sugarman,
4
Benjamin S. Cramer,
1,5
Nicholas Christie-Blick,
3
Stephen F. Pekar
3,6
We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on
various time scales and present a new sea-level record for the past 100 million years
(My). Long-term sea level peaked at 100 T 50 meters during the Cretaceous, implying
that ocean-crust production rates were much lower than previously inferred. Sea level
mirrors oxygen isotope variations, reflecting ice-volume change on the 10
4
-to10
6
-year
scale, but a link between oxygen isotope and sea level on the 10
7
-year scale must be
due to temperature changes that we attribute to tectonically controlled carbon dioxide
variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry,
and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past
100 My, sea-level changes reflect global climate evolution from a time of ephemeral
Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in
Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern
Hemisphere ice sheets (2.5 Ma to the present).
F
luctuations in global sea level (eustasy)
result from changes in the volume of
water in the ocean or the volume of
ocean basins (Fig. 1) (1–4). Water-volume
changes are dominated by growth and decay of
continental ice sheets, producing high-
amplitude, rapid eustatic changes Eup to 200
m and 20 m per thousand years (ky)^. Other
processes that affect water volume occur at
high rates (10 m/ky) and low amplitudes (È5
to 10 m): desiccation and inundation of mar-
ginal seas, thermal expansion and contraction
of seawater, and variations in groundwater and
lake storage. Changes in ocean basin volume
are dominated by slow variations in sea-floor
spreading rates or ocean ridge lengths (100 to
300 m amplitude, rates of 10 m/My). Variations
in sedimentation cause moderate amplitude
(60 m), slow changes (10 m/My). Emplace-
ment of oceanic plateaus produces moderate-
ly rapid rises (60 m/My) but slow falls due to
thermal subsidence (10 m/My).
Eustatic variations can be estimated from
satellite measurements, tide gauges, shoreline
markers, reefs and atolls, oxygen isotopes
(d
18
O), and the flooding history of continental
margins and cratons. Satellite measurements
are limited to the past 10 years (5), whereas
tide gauge records extend back only È150
years (3). The most recent pre-anthropogenic
sea-level rise began at about 18 ka and can be
measured by directly dating shoreline markers
(fig. S1). Tropical reefs and atolls (fig. S2)
provide the most reliable geological estimates
by dating Bfossil sunshine[ (e.g., shallow-
dwelling corals) and have provided a precise
estimate for the last sea-level lowstand (120 T
5 m below present at 18 ka) (fig. S2) (6, 7).
However, most coral records are from regions
with complicated uplift/subsidence histories,
are difficult to recover and date (particularly
beyond a few 100 ky), and have poorly pre-
served lowstand deposits.
The growth and decay of continental ice
sheets causes eustatic changes that are in-
directly recorded in the chemistry of forami-
nifera because ice has lower d
18
O values than
seawater (fig. S2) Ee.g., (8, 9)^. Oxygen isotope
values provide a proxy for glacioeustasy, but
d
18
O-based reconstructions are subject to
several uncertainties: (i) Calcite d
18
Ovalues
also vary as a function of temperature. (ii)
Surface-ocean d
18
O values are influenced by
local evaporation-precipitation effects on
seawater. (iii) Postdepositional alteration (dia-
genesis) may overprint original d
18
Ovalues,
limiting useful records to sediments younger
than 100 My.
Continents have been flooded many times
in the geologic past (Fig. 2). However, the
flooding record is not a direct measure of
eustatic change because variations in sub-
sidence and sediment supply also influence
shoreline location. Regional unconformities
(surfaces of erosion and nondeposition) divide
the stratigraphic record into sequences and
provide a key to eustatic change. Unconform-
ities result from sea-level fall or tectonic uplift
(10–12). Similar ages of sequence boundaries
on different continents have been interpreted
as indicating that the surfaces were caused by a
global process, eustasy Ee.g. (10, 11)^. The link-
age with d
18
O increases for the past 40 My
(13) indicates that most sequence boundaries
resulted from eustatic falls driven by the
growth of continental ice sheets.
Although unconformities poten-
tially provide the timing of eustatic
lowstands, extracting global sea-
level history from the stratigraphic
record requires a quantitative method
that distinguishes the contributions
of eustasy, subsidence, and sedi-
ment accumulation. Backstripping
is an inverse technique that can be
used to quantitatively extract sea-
level change amplitudes from the
stratigraphic record. It accounts for
the effects of sediment compac-
tion, loading (the response of crust
to overlying sediment mass), and
water-depth variations on basin sub-
sidence (14). Tectonic subsidence at
a passive margin is modeled with
thermal decay curves and removed
REVIEW
1
Department of Geological Sciences, Rutgers University,
Piscataway, NJ 08854, USA.
2
Department of Geo-
sciences, Western Michigan University, Kalamazoo, MI
49008–5150, USA.
3
Lamont-Doherty Earth Observa-
tory of Columbia University, Palisades, NY 10964, USA.
4
New Jersey Geological Survey, Post Office Box 427,
Trenton, NJ 08625, USA.
5
Department of Geological
Sciences, University of Oregon, Eugene, OR 97403–
1272, USA.
6
School of Earth and Environmental
Sciences, Queens College, 65-30 Kissena Boulevard,
Flushing,NY11367,USA.
*To whom correspondence should be addressed:
kgm@rci.rutgers.edu
Fig. 1. Timing and amplitudes of geologic mechanisms of
eustatic change derived from (1–4). SF, sea floor; Cont,
continental.
www.sciencemag.org SCIENCE VOL 310 25 NOVEMBER 2005
1293

to obtain a quantified eustatic estimate in the
absence of local tectonic complexities.
We review the record of and uncertainties
in eustatic changes over the past 543 My on
three time scales: (i) a long-term trend (10
7
to
10
8
years) that has been attributed largely to
variations in sea-floor spreading; (ii) the 10
6
-
year scale that is among the most prominent
features of the stratigraphic record; and (iii) the
10
4
-to10
5
-year scale that is dominated by
changes in ice volume and controlled by astro-
nomical variations in insolation. We present a
new eustatic record for the past 100 My, with
implications for causal mechanisms for both
10
7
- and 10
6
-year changes.
Long-Term Flooding of Continents
Sloss (15) recognized that North America
experienced five major Phanerozoic floodings
(Fig. 2) and attributed these changes to sub-
sidence and uplift of the craton. Vail and col-
leagues at Exxon Production Research Company
(EPR) recognized similar 10
7
-to10
8
-year scale
‘‘supersequences’’ that they attributed to global
sea-level changes (10, 11, 16). Others have re-
constructed continental flooding history on the
10
7
-to10
8
-year scale (4, 17–19) (Fig. 2) and
inferred eustatic changes from commonalities
among continents.
High Late Cretaceous sea level has been
attributed to high ocean-crust production rates
that resulted in more buoyant ridges displacing
seawater onto low-lying parts of continents
(‘‘tectonoeustasy’’) (20). This concept has been
extended to the Paleozoic through Early Meso-
zoic by assuming that 10
7
-to10
8
-year scale
continental flooding was caused by high sea-
floor spreading rates, even though direct evi-
dence for sea-floor spreading rates is absent
owing to subduction.
Our sea-level record for the past 100 My
has much lower amplitudes on the 10
7
-to
10
8
-year scale than previously inferred (Figs.
2 and 3 and fig. S3), with implications for sea-
level change from 543 to 100 Ma. Our 100 to
7 Ma record (Fig. 2) is based on backstripping
stratigraphic data from five New Jersey coast-
al plain coreholes (21, 22). Similar estimates
obtained for each site suggest that we suc-
cessfully accounted for the effects of thermal
subsidence, sediment loading, compaction, and
water-depth variations. Our long-term trend in-
dicates that sea level was 50 to 70 m above
present in the Late Cretaceous (È80 Ma),
roseto70to100mfrom60to50Ma,andfell
by È70 to 100 m since 50 Ma (23). This con-
trasts with previously reported Late Cretaceous
sea-level peaks of about 250 to 320 m based
on sea-floor spreading reconstructions (2), al-
though it is within error estimates of 45 to 365 m
(best estimate 230 m) (24). It is lower than
global continental flooding estimates [150 m
(19), 80 to 200 m (18)].
Our results are similar to backstripped
estimates from the Scotian and New Jersey con-
tinental shelves (14), although the Late Creta-
ceouspeakislower(50to70mversusÈ110 m)
(fig. S3). One-dimensional (1D) backstripping
may underestimate the Late Cretaceous peak
because coastal plain subsidence results from
athermoflexuraleffect(14), and thermal sub-
sidence curves may slightly overestimate the
tectonic portion of subsidence of the older sec-
tion. Considering backstripping and continental
flooding estimates (18, 19) and errors in our
paleowater depth estimates (eustatic error of
T10 to 35 m), we conclude that sea level in the
Late Cretaceous was 100 T 50 m higher than it
is today.
Using new sea-floor age data, Rowley (25)
suggested that there have been no changes in
sea-floor spreading rates over the past 180 My.
Our record implies a modest decrease in the
rate of ocean-crust production because the long-
term eustatic fall of 70 to 100 m since the early
Eocene (Fig. 3) cannot be totally ascribed to
permanent growth of ice sheets (26).
Fig. 2. Comparison of Phanerozoic backstripped eustatic estimates of this
study, Watts (14), Sahagian (35), Kominz (29), Levy (30), and Bond (18);
EPR records of Vail (10)andHaq(11, 16); continental flooding records of
Sloss (15) and Ronov (17) plotted versus area, and Bond (18), Harrison (19),
and Sahagian (4) plotted versus sea level; and evolutionary records compiled
by Katz (52).
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Our observation that long-term eustatic
changes were appreciably smaller than previ-
ously thought has implications for geochemical
models [e.g., (27)] that have used sea-level
records to scale ocean production rates. Es-
timates derived from backstripping from the
past 170 My (Fig. 2) show much
lower long-term amplitudes than
those published by EPR. Back-
stripped sea-level records from the
Cambrian-Devonian of the western
United States show È200-m ampli-
tudes on the 10
7
-year scale (28–30)
(Fig. 2), although a Cambrian-
Ordovician backstripped data set
from the Appalachians shows a
lower (È70 m) amplitude (Fig. 2)
(28). The sea-level rise in the
Cambrian is attributed to the gen-
eration of new ocean ridges with
the breakup of Pannotia (29), but
the amplitude of this rise is still
uncertain. Although the jury is still
out on the amplitudes of Paleozoic
sea level on the 10
7
-year scale,
our work suggests that the EPR
records cannot be used to scale
past spreading rates.
Sea-level changes on very
long time scales (250 My) are
related to the assembly and break-
up of supercontinents. Formation
of the supercontinents Pannotia
(late Proterozoic to Early Cambri-
an) and Pangea (Permian to early
Triassic) was associated with low
levels of continental flooding (Fig.
2). This may be attributed to (i) a
eustatic effect due to thickening of
continents during orogeny result-
ing in increased oceanic area (2)
and/or (ii) higher elevations that
result when trapped heat builds up
below the supercontinents (31).
Million-Year Scale Changes
In 1977, EPR surprised academic
and industrial colleagues with the
publication of a Phanerozoic eustatic
record that showed more than 50
falls, some as large as 400 m (10). In
1987, the EPR group published a
series of papers, including a syn-
thesis in Science (11) that reported
more than 100 sea-level falls dur-
ing the past 250 My, with a max-
imum fall of 160 m. The EPR
studies came under intense scru-
tiny because of the novel sugges-
tions that (i) sequence boundaries are time-
important features that could be recognized on
seismic profiles and (ii) seismic profiles could
be used to determine the history of sea level.
The EPR curves have been strongly criticized
for their methodology (12, 32), with critics sug-
gesting that coastal onlap curves presented
cannot be translated into a eustatic estimate.
Drilling on the New Jersey margin has
provided new insights into the amplitudes of
and mechanisms for 10
6
-year scale sea-level
changes. Fourteen Late Cretaceous sequences
and 33 Paleocene-Miocene sequences were
identified in New Jersey coastal plain core-
holes (13, 33) and dated by integrating bio-
stratigraphy, Sr-isotopic stratigraphy, and
magnetostratigraphy to produce a chronology
with age resolution of better than T0.5Myfor
the Cenozoic (13)andT1.0MyfortheLate
Cretaceous (33). Onshore New Jersey se-
quence boundaries correlate with sequence
boundaries in the Bahamas, northwest Europe,
the U.S. Gulf Coast, Russia, offshore New Jer-
sey, and those of EPR, which suggests that
they are global and formed in
response to eustatic falls (13, 33).
Thus, drilling has validated the
number and timing, although
not the amplitude, of many of
the EPR sea-level events for the
past 100 My (13, 33). Oligocene-
Miocene sequence boundaries
can be firmly linked with global
d
18
O increases, demonstrating a
causal relation between sea level
and ice volume (13, 33), as ex-
pected for the Icehouse world of
the past 33 My.
Backstripping of the New
Jersey records provides eustatic
estimates from È100 to 7 Ma
(Fig. 3). Paleocene-Eocene and
Miocene estimates are derived
from 1D backstripped records
from five sites and Late Creta-
ceous sequences from two sites
(34). Several Upper Cretaceous
onshore sections capture full
amplitudes of change; howev-
er, many Cretaceous and most
Cenozoic onshore sections do
not record sea-level lowstands.
Eustatic estimates for the latest
Eocene to earliest Miocene are
derived from 2D backstripping
(22) that addressed this problem.
Our backstripped eustatic es-
timate (table S1) shows that
global sea level changed by 20
to 80 m during the Late Creta-
ceous to Miocene (this study)
and the Middle Jurassic to Late
Cretaceous (35). Our compari-
son shows that the amplitudes of
the EPR sea-level curve, includ-
ing the most recent update (16),
are at least 2.5 times too high
(Fig.2andfig.S3).
Eustatic changes with ampli-
tudes of 10s of meters in less
than 1 My pose an enigma for
a supposedly ice-free Green-
house world, because ice-volume
changes are the only known
means of producing such large
and rapid changes. Our record
(Fig. 3) quantifies high ampli-
tudes and rates of eustatic change (925 m in
G 1 My) in the Late Cretaceous to Eocene
Greenhouse world. Based on the sea-level
history, we have proposed that ice sheets
existed for geologically short intervals (i.e.,
lasting È100 ky) in the previously assumed
Fig. 3. Global sea level (light blue) for the interval 7 to 100 Ma derived by
backstripping data (21). Global sea level (purple) for the interval 0 to 7 Ma derived
from d
18
O,shownindetailonFig.4.Shownforcomparisonisabenthic
foraminiferal d
18
O synthesis from 0 to 100 Ma (red), with the scale on the
bottom axis in ° [reported to Cibicidoides values (0.64° lower than
equilibrium)]. The portion of the d
18
Ocurvefrom0to65Maisderivedusing
data from Miller (44) and fig. S1 recalibrated to the time scale of (71). The d
18
O
curve from 65 to 100 Ma is based on the data compiled by Miller (36) calibrated
to the time scale of (72). Data from 7 to 100 Ma were interpolated to a constant
0.1-My interval and smoothed with a 21-point Gaussian convolution filter using
Igor Pro. Pink box at È11 Ma is sea-level estimate derived from the Marion
Plateau (51). Heavy black line is the long-term fit to our backstripped curve
(23). Light green boxes indicate times of spreading rate increases on various
ocean ridges (57). Dark green box indicates the opening of the Norwegian-
Greenland Sea and concomitant extrusion of the Brito-Arctic basalts.
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ice-free Late Cretaceous-Eocene Greenhouse
world (36). This view can be reconciled with
previous assumptions of an ice-free world.
Sea-level changes on the 10
6
-year scale were
typically È15 to 30 m in the Late Cretaceous-
Eocene (È100 to 33.8 Ma), suggesting growth
and decay of small- to medium-sized (10 to
15  10
6
km
3
) ephemeral Antarctic ice sheets
(36). These ice sheets did not reach the Ant-
arctic coast; as a result, coastal Antarctica and
deep-water source regions were warm even
though there were major changes in sea level
as the result of glaciation (36). These ice sheets
existed only during ‘‘cold snaps,’’ leaving Ant-
arctica ice-free during much of the Greenhouse
Late Cretaceous to Eocene (36).
Sea-level changes on the 10
6
-year scale
occurred throughout the Phanerozoic. Studies
from the Russian platform and Siberia provide
backstripped records of 10
6
-year sea-level
changes that are remarkably similar to New
Jersey in the interval of overlap and extend to
the Middle Jurassic (È170 Ma) (35). The strat-
igraphic record before 170 Ma is replete in
10
6
-year sea-level changes (16, 37). However, it
is unclear whether these variations represent
global changes in sea level. Eustatic estimates
have been extracted from backstripping of Pa-
leozoic strata (28, 29) (Fig. 2), although differ-
ences in the Appalachian versus the western
U.S. Cambrian-Ordovician sea-level amplitude
estimates are large, and thus the eustatic imprint
is ambiguous.
Eustatic changes on the 10
4
-to10
6
-year
scales were controlled primarily by variations
in ice volume during the past 100 My and
may be expected to be modulated by both
short-period [19/23 (precession), 41 (tilt), and
È100 ky (precession)] and long-period [1.2
(tilt) and 2.4 My (precession)] astronomical
variations (38). Spectral analysis of our sea-
level records shows that variations occur with
an as-yet-unexplained, persistent 3-My beat
and a second primary period varying from 6
to 10 My (fig. S4). Amplitudes in the È3-My
bandwith are È10mfrom60to20Ma,with
lower amplitude from 90 to 60 Ma.
The existence of continental ice sheets in the
Greenhouse world is a controversial in-
terpretation, but the study of ice-volume history
has progressively tracked ice sheets back through
the Cenozoic (36). After extensive debate, a
consensus has developed that ice volume
increased markedly in the earliest Oligocene
(8, 9). We suggest that, at that time, the Ant-
arctic ice sheet began to be a forcing agent of,
and not just a response to, ocean circulation
(36). The Antarctic continent (including west
Antarctica) (39) was entirely covered by ice, and
sea level was lower by È55 m (22). As a result,
latitudinal thermal gradients (40) and deep-water
circulation rates increased [with pulses of
Southern Component and Northern Component
Water (41)]. Diatoms diversified rapidly in
response to increased surface-water circulation
and nutrient availability (Fig. 2), resulting in
increased export production and a positive
feedback on CO
2
drawdown and cooling.
The earliest Oligocene event represented a
major change in climate state from a Greenhouse
world with cold snaps to the Icehouse world that
continues today. Sea-level changes from the
Oligocene to the early Pliocene (È33.8 to 2.5
Ma) were È30 to 60 m (Figs. 3 and 4), with
growth and decay of a large (up to present
volumes of 25  10
6
km
3
) ice sheet mostly in
Antarctica. A middle Miocene d
18
Oincreaseis
associated with deep-water cooling and two
ice-growth events that resulted in the permanent
development of the East Antarctic ice sheet
(40). Northern hemisphere ice sheets (NHIS)
have existed since at least the middle Miocene
(41), but large NHIS with sea-level changes of
60 to 120 m only began during the late Pli-
ocene to Holocene (È2.5to0Ma)(Fig.4).
Milankovitch Scale Changes
The growth and decay of NHIS (the late
Pliocene-Holocene ‘‘ice ages’’) and attendant
sea-level changes were paced by 10
4
-to10
5
-
year scale Milankovitch changes. The d
18
O
record shows a dominant 100 ky (eccentricity)
beat over the past 800 ky, with secondary 19/23
(precession) and 41-ky (tilt) periods (42). Be-
fore È800 ky, the tilt cycle dominated d
18
O
(43) and sea-level records. Although strong
precessional and eccentricity beats occur in the
carbon system, the tilt cycle has dominated
d
18
O and ice-volume records for much of the
past 33.8 My (9). Growth and decay of small-
to medium-sized ice sheets in the Late
Cretaceous-Eocene on the Milankovitch scale
probably lie near or below the detection limit
of d
18
O records [È 0.1 per mil (°) 0 10-m
eustatic change].
Continental margins record 10
4
-to10
5
-year
scalesea-levelchangesonlyinveryhighsed-
imentation rate settings. Foraminiferal d
18
O
records reflect ice volume in addition to tem-
perature changes and potentially provide a
proxy for sea-level changes on the 10
4
-to
10
5
-year scale. The d
18
O record provides con-
tinuity and excellent age control, although
assumptions about thermal history must be
made to use it as a sea-level proxy. In addition,
diagenesis complicates planktonic foraminiferal
d
18
O records, although benthic foraminifera
generally show little evidence for diagenesis
at burial depths less than 400 to 500 m (44).
We derive sea-level estimates from 9 to
0 Ma using benthic foraminiferal d
18
O records
because the New Jersey record is incomplete
from 7 to 0 Ma (table S1). We scaled the ben-
thic foraminiferal d
18
Orecord(45)tosealevel
by making minimum assumptions about ocean
thermal history (Fig. 4). The resultant sea-level
curve (Fig. 4) aligns remarkably well with the
backstripped record from 9 to 7 Ma (Fig. 3).
Our d
18
O-derived sea-level estimate for the
past 9 My (Fig. 4) shows that the record is
dominated by the response to the 41-ky peri-
od tilt forcing, which increases in amplitude
toward the present, and a low-amplitude È21-ky
precession response. The major 100-ky events
of the past 900 ky stand out in the sea-level
record (Fig. 4). There are prominent 10
6
-year
scale sea-level falls (the 2.5, 3.3, 4.0, 4.9, 5.7,
and 8.2 Ma events) (Fig. 4), but these are not
obviously paced by amplitude modulations of
either precession or tilt (fig. S4).
Suborbital Scale
Very large (9100 m) sea-level rises are associ-
ated with glacial terminations of the past 800 ky
(fig. S1) (6).Themostrecentrisethatfollowed
the last glacial maximum at 18 ka occurred
as two major steps associated with meltwater
pulses (MWP) 1a (13.8 ka) and 1b (11.3 ka),
punctuated by a slowing at È12 ka (6). Sea-
level rise slowed at about 7 to 6 ka (fig. S1).
Some regions experienced a mid-Holocene sea-
level high at 5 ka, but we show that global sea
level has risen at È1 mm/year over the past 5
to 6 ky. We present new core data from New
Jersey covering the past 6 ky that show a rise
of 2 mm/year over the past 5 ky (fig. S1). This
New Jersey curve is remarkably similar to
sea-level records from Delaware (46) and south-
ern New England (47), with a eustatic rise of
1 mm/year over the past 5 ky once corrected
for subsidence effects (48), virtually identical
to that obtained from Caribbean reef localities
(49) (fig. S1) accounting for subsidence.
Error Estimates
Long-term sea-level estimates show consider-
able differences, with a large range of Late
Cretaceous sea-level estimates: È110 m (14),
150 m (19), 250 m (4),and80to200m(18),
and our best estimate of 100 T 50 m. We con-
clude that sea-level amplitudes on this scale
were substantially lower than generally believed
(100 versus 250 m) over the past 170 My, with
uncertain amplitude before this (Fig. 2).
Sea-level estimates on the 10
6
-year scale
have an uncertainty, typically, of at best T10 to
T50 m. The two main sources of errors in
backstripping relate to hiatuses (time gaps) and
paleowater depth estimates. New Jersey coastal
plain sequences represent primarily inner-shelf
to middle-shelf environments, with eustatic
errors from paleowater depth estimates of T10
to 20 m (50). Hiatuses in our record potentially
explain why amplitudes of change might not be
fully recorded, and the effect of hiatuses can be
evaluated only by comparing our record with
other regions. Drilling on the Marion Plateau
(offshore northeast Australia) targeted an È11 Ma
eustatic lowering (51); backstripping yields a
sea-level estimate of 56.5 T 11.5 m for this
event (pink bar on Fig. 3). Our estimate for
this event is È40 T 15 m (Fig. 1); these esti-
mates are consistent, within error, but suggest
that we may underestimate sea-level falls by 5
to 30 m.
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The record of the past 130 ky illustrates the
errors in converting a d
18
O record into a sea-
level proxy (fig. S1). Benthic foraminiferal
d
18
O records can be scaled to a faithful proxy
for glacial to cool interglacials [Marine Isotope
Chron (MIC) 2d to 5d] (fig. S2), with sea level
and d
18
O in phase and lagging insolation.
However, large deviations of the d
18
O-based
sea-level curve occur during peak warm in-
tervals (Holocene and MIC 5e) (Fig. 2), with a
hint that deep-sea temperature change leads
sea level. We have attempted to correct for this
temperature effect by scaling to the
Barbados sea-level record (6). How-
ever, this results in underestimating
amplitudes of glacials and overesti-
mating amplitudes of interglacials,
with a resultant 20% uncertainty.
Relation of Sea Level to
Evolution and Climate
Changes
Episodes of supercontinent rifting
and sea-level rise on the 10
7
-to
10
8
-year scale played a role in
phytoplankton evolution since the
Proterozoic by flooding continental
shelves and low-lying inland areas
and increasing the total length of
coastline. The resulting increases in
habitat heterogeneity, ecospace, and
nutrient availability favored plankton
that lived along continental margins.
Accordingly, diversity increases in
phytoplankton (Fig. 2) appear to
correlate with continental rifting of
Pannotia (Early Paleozoic) and
Pangea (Jurassic) (Fig. 2), ultimate-
ly resulting in the three groups of
eukaryotic phytoplankton (cocco-
lithophores, diatoms, and dinoflag-
ellates) that dominate the modern
ocean (52).
Sea-level changes are expected
with beats of 19/23, 41, and 100 ky,
but similar changes on the 10
6
-year
scale (Fig. 3) have puzzled geolo-
gists. Sea-level cyclicity on the 10
6
-
year scale can be explained by a
modulation of the shorter term
Milankovitch-scale sea-level events
(fig. S5). For example, a promi-
nent seismic disconformity spanning
the Oligocene/Miocene boundary
(È23.8 Ma) on the New Jersey slope (13)
can be correlated to a detailed d
18
O record at
deep-sea Site 929 (53), showing that the 10
6
-
year scale sea-level fall at the Oligocene/
Miocene boundary occurred as a series of
41-ky d
18
O increases and sea-level changes.
The 41-ky sea-level falls are reflected in core
photographs by a series of dark-light changes
(fig. S5), resulting from variations in glauco-
nite transported downslope during lowstands.
The seismic reflection is a concatenation of
these beds and the ice-volume events that
caused them.
The high sea levels of the Late Cretaceous
and early Eocene are associated with peak ben-
thic foraminiferal d
18
O values (Fig. 3) (table
S1), and it has long been suggested that sea
level covaries with d
18
O on the 10
7
-year scale
[e.g., (54)]. On the 10
5
-to10
6
-year scales, such
covariance can be explained by ice-volume
changes in concert with temperature changes
(8, 13). However, this cannot be true on the
10
7
-to10
8
-year scale because most of the
d
18
O signal must be attributed to temperature
changes. For example, 3.6° of the 4.4°
increase from 50 to 0 Ma (Fig. 3) must be
attributed to deep-water cooling (15-C overall)
rather than to ice storage (55). The link
between sea level and temperature on the
10
7
-to10
8
-year scale cannot be due to cooling
alone, because this would explain only È15 m
of eustatic fall since 50 Ma. The link between
d
18
O and sea-level variations on the 10
7
-to
10
8
-year scale can be explained by CO
2
variations controlled by tectonics (changes in
ocean-crust production and mountain uplift).
High ocean-crust production rates have
long been linked to high sea level, high CO
2
,
and warm global temperatures [e.g., (54)]. Warm
Late Cretaceous climates and elevated sea
level may be attributable to moderately high-
er sea-floor production rates, although our
results require that crustal production rates
were lower than previously thought. However,
the intensity of spreading ridge hydrothermal
activity (a major source of CO
2
outgassing)
appears also to correlate with
times of major tectonic reor-
ganizations (56). We propose that
the early Eocene peak in global
warmth and sea level (Fig. 3) was
due not only to slightly higher
ocean-crust production but also to
a late Paleocene-early Eocene tec-
tonic reorganization. The largest
change in ridge length of the past
100 My occurred È60 to 50 Ma
(57), associated with the open-
ing of the Norwegian-Greenland
Sea, a significant global reor-
ganization of spreading ridges,
and extrusion of 1 to 2  10
6
km
3
of basalts of the Brito-
Arctic province (58). A late
Paleocene to early Eocene sea-
level rise coincides with this
ridge-length increase, suggesting
a causal relation. We suggest
that this reorganization also in-
creased CO
2
outgassing and
caused global warming to an
early Eocene maximum. Subse-
quent reduced spreading rates
and hydrothermal activity re-
sultedinlowerlong-termsea
level, reduced CO
2
outgassing,
and a cooling of deep-water by
È8-C(44). CO
2
may have been
further lowered by an increase in
continental weathering rates dur-
ing the remainder of the Cenozo-
ic (59), explaining an additional
deep-water cooling of 7-Cto
9-C(44).
Our studies of the past 100
My provide clues to the tempo of
climate and ice-volume changes
for other Icehouse and Green-
house worlds of the Phanerozoic (Fig. 2).
Icehouse worlds of the past 33 My, the Penn-
sylvanian to Early Permian, Late Devonian,
and Late Ordovician (60), can be characterized
by ice-volume changes that caused sea-level
variations up to 200 m. Greenhouse worlds
characterize much of the Phanerozoic, but we
note that small (10 to 15  10
6
km
3
), ephem-
eral ice sheets occurred in the Greenhouse of
the Late Cretaceous to Eocene. This raises
the question as to whether any portion of the
Fig. 4. Oxygen isotopic-based sea-level estimate for the past 9 My.
Isotopic values are reported to equilibrium, with coretop and last glacial
maximum values indicated with arrows and thin vertical green lines. Thin
black line is raw data plotted versus the d
18
O scale (bottom). The purple
line is the sea-level estimate (top scale), which is derived by correcting
the d
18
O data by 0.5° due to a È2-C cooling between 3.3 and 2.5 Ma
(red line), scaling by d
18
O to sea level using a calibration of 0.1°/10 m,
and scaling the result by 0.8 (45).
R EVIEW
www.sciencemag.org SCIENCE VOL 310 25 NOVEMBER 2005
1297

Phanerozoic was ice-free. The Triassic and
Cambrian pose two of the best candidates for
an ice-free world (60), yet Haq (11, 16) noted
numerous 10
6
-year scale sea-level variations
at these times (Fig. 2). If corroborated, these
changes suggest the presence of ephemeral ice
sheets even in the warmest of the Greenhouse
periods.
References and Notes
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O records from 846 [0 to 6.136
Ma, equatorial Pacific (67)] and 982 [6.139 to 9 Ma,
northern North Atlantic (68)] were spliced to create a
high-resolution d
18
O composite record with a sample
resolution of 3 ky for the late Miocene to the present.
Although they are located in different deep-water
masses, the records yield similar values across the
splice. The pre–late Pliocene d
18
O record has average
values (2.9°) that are 0.5° lowerthanmodernvalues
(3.4°). Ice volumes during the late Miocene to early
Pliocene were similar to the modern (69), indicating
that this long-term d
18
O offset reflects deep-water
temperatures that were warmer relative to the modern.
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than 3.5 Ma as a linear function from 2.5 to 3.5 Ma. We
converted the adjusted d
18
O composite record to a
sea-level estimate (Fig. 2) by scaling to a calibration of
0.1°/10 m. Our initial sea-level and d
18
Oestimates
showed a change from the last glacial maximum to
modern changes of 1.5°; this change has been
calibrated in Barbados as 1.2°. The difference is due
to glacial-interglacial deep-sea temperature changes of
È2-C(6), as illustrated on Fig. 3. We scaled the sea-
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outer-shelf (T50 m), and slope (T200 m) environments.
The errors in paleowater depth estimates correspond to
eustatic errors correcting for loading of T10, 20, 35, and
120 m, respectively. Most of our sections are inner to
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73. We thank W. Van Sickel and A. Stanley for con-
tributions to development of the sea-level curves,
D. Sahagian for reviews, P. Falkowski and D. Kent for
comments, and the members of the Coastal Plain
Drilling Project (ODP Legs 150X and 174AX) who
are not listed here for contribution of critical data
sets that led to the curve. Supported by NSF grants
OCE 0084032, EAR97-08664, EAR99-09179, and
EAR03-07112 (K.G.M.); EAR98-14025 and EAR03-
7101 (M.A.K.); and the New Jersey Geological Sur-
vey. Samples were supplied by the Ocean Drilling
Program.
Supporting Online Material
www.sciencemag.org/cgi/content/full/310/5752/1293/
DC1
Figs. S1 to S5
Table S1
10.1126/science.1116412
R EVIEW
25 NOVEMBER 2005 VOL 310 SCIENCE www.sciencemag.org
1298

www.sciencemag.org/cgi/content/full/310/5752/1293/DC1
Supporting Online Material for
The Phanerozoic Record of Global Sea-Level Change
Kenneth G. Miller,* Michelle A. Kominz, James V. Browning, James D. Wright,
Gregory S. Mountain, Miriam E. Katz, Peter J. Sugarman, Benjamin S. Cramer,
Nicholas Christie-Blick, Stephen F. Pekar
*To whom correspondence should be addressed: kgm@rci.rutgers.edu
Published 25 November 2005, Science 310, 1293 (2005)
DOI: 10.1126/science.1116412
This PDF file includes:
Figs. S1 to S5
Table S1
References

Figure Captions (Supplementary Online Material)
Fig. S1. Compilation of Holocene relative sea-level records from the western North Atlantic.
Records are from New Jersey (blue/green symbols from this study and red symbols from N.
P. Psuty, Physical Geography, 7, 156 (1986), Delaware (46)southern New England (47), and
a Caribbean reef compilation (49) with a polynomial fit from 8-0 ka (6) and a linear fit from
5-0 ka (this study).
Fig. S2. Comparison sea-level record from the Huon New Guinea terraces (7) and Barbados (6)
and benthic foraminiferal δ
18
O record from Pacific (Carnegie Ridge) core V19-30 (N. J.
Shackleton, N. G. Pisias, in The Carbon Cycle and Atmospheric CO
2
, E. T. Sunquist, W. S.
Broecker, Eds. (American Geophysical Union, Washington, D.C., 1985), pp. 303-317.). Grey
curve at bottom shows variations in insolation for June at 65°N latitude. 0 is modern sea
level.
Fig. S3. Comparison of the sea-level estimate and δ
18
O record from Figure 3 with the sea-level
record of Haq (11), the long-term record of Watts (14) from backstripping of the Scotian
shelf and New Jersey outer continental shelf, and the backstripped record of Sahagian (35)
from the Russian platform and Siberia. Note that the scale for the Haq estimates (green axis)
is 2 times that of our sea-level estimate (blue line and axis). Watts and Sahagian curves are
plotted using the blue axis.
Fig. S4. Spectral content of the sea-level curve. The sea-level curve is shown at the top in black,
with a 0.1 my Gaussian interpolation that was used for spectral analysis shown in red. To the
right is the periodogram of the data in black with the expected red noise spectrum in red. The
image shows variation in spectral power through time calculated using the Gaussian Wigner
Transform implemented by Igor Pro™. Spectral power is indexed to colors according to the
scale in the upper right. Note that the vertical period and frequency axis are log
2
scales, but
with tick marks at linear intervals.
Fig. S5. Benthic foraminiferal δ
18
O data (13) from Ocean Drilling Program Site 904 (NJ
continental slope) plotted versus depth showing magnetic chronozone, core photographs,
reflectivity, and core log impedance. Also shown are δ
18
O records from South Atlantic Site
929 (53) that allow correlation to the Site 904 record. Red curve is plotted versus depth while
the black is plotted versus age scale.

REFERENCES
6. R. G. Fairbanks, Nature 339, 532 (1989).
7. J. Chappell et al., Earth Planet. Sci. Lett. 141, 227 (1996).
11. B. U. Haq, J. Hardenbol, P. R. Vail, Science 235, 1156 (1987).
14. A. B. Watts, M. Steckler, Ewing Series 3, 218 (1979).
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Geol. Bull. 80, 1433 (1996).
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(2004).
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0200040006000800010000
Age, yr
Depth, m
New Jersey = 1.9 mm/yr
Delaware
So. New England
Holocene Sea Level,
Western North Atlantic
0
5
10
15
Reefs regression =
1.26 mm/yr
Miller et al., Science, Fig. S1
Caribbean Reefs
other New JerseyIsland Beach
other New JerseyGreat Bay 2
Union BeachCape May
Great BayGreat Bay 1
CheesequakeRainbow Island

3.0
3.5
4.0
4.5
5.0
5.5
δ
18
O ‰
-150
-50
0
50
100
Elevation (m)
0 50 100 150
Age (ka)
1
2
3a
3b
3c
4
5a
5b
5c
6
5d
5e
Insolation
(W/m
2
)
Barbados
New Guinea
450
500
550
Oxygen isotopes, V19-30
Insolation
1
2
NCW-SO
Miller et al., Science, Fig S2

Miller et al., Science Fig. S3
Foram.
P21b
P21a
P14
P22
M2
M3
M4
M5
M7
P18
P19
P16
P20
P15
P12
P11
P10
P9
P7
P6b
P6a
P5
P4c
P4b
P4a
P3b
P3a
P1c
P1b
P1a
Pα-0
M13
PL1
PL5
Pt1a
P13
P17
M1
M6
M12
M9
M14
P2
P8
20
40
60
10
0
30
50
Age (Ma)
70
80
90
100
Epoch/Age
late
middle
early
Oligocene
late
Miocene
earlylate
Eocene
middle
early
Paleocene
late
early
Late Cretaceous
Plio.
Pleis.
e. l.
e.
m.
MaastrichtianCampanianSantonian
Coniacian
Turonian
Cenomanian
14a
Nanno.
1
2
3
4
5
6
7
9
25
24
23
22
21
19
-20
18
17
16
15c
15b
15a
14b
13
12
11
10
9
8
6
5
4
3
2
1
10
11
NP Zones
NN Zones
13
16
19
10
26
24
23
21
20
19
18
14
13
12
11
22
25
9
a
b
c
16
15
17
7
CC Zones
Chrons
Polarity
C6AA
C5AD
C6C
C6B
C6A
C6
C5E
C5D
C5C
C5B
C5A
C5
C13
C12
C11
C10
C9
C8
C7
C15
C17
C7A
C18
C19
C20
C21
C22
C23
C24
C25
C26
C27
C28
C29
C4A
C4
C3A
C3
C2A
C2
C1
C5AB
C30
C31
C32
C33
C34
C16
-50 0 50 100 150-100
large NHIS
Large Antarctic Ice Sheets
Small Antarctic Ice Sheets
8.2
64.3
57.3
60.8
54.9
53.9
53.2
49.2
48.1
47.0
45.6
42.7
39.7
36.4
34.7
33.7
33.1
32.1
29.9
28.2
26.3
24.1
22.0
20.1
19.5
18.3
16.5
15.4
14.3
13.3
11.0
9.4
97.0
94.7
93.7
92.0
90.0
88.3
86.7
83.0
84.3
83.7
77.5
76.1
71.2
66.9
98.4
5.7
4.9
4.0
3.3
2.5
Kw-Ch
Kw1a
Kw2a
E3
E4
E5
E6
E7
E8
E9
Pa3
Pa4
Pa2
O3
O4
O5
O6
Ch2?
Nav1
Marsh
Merch III
Ch
MII
MI
BIII
BII
BI
MIII
Eng
Pa1
Kw3
Kw0
Haq sea Level (m)
Sea Level (m)
Sahagian
Watts
Haq
-200 0 200
Kw2b/Kw2c
Kw1b/Kw1c
E10/E11
O1/O2
E1/E2
MI/MII
50.7
E6a

Miller et al., Science, Fig. S4

Core-log
impedance
Reflectivity coefficient
Chron
Gray scale
Dark
Light
200
C6C
n1
n2/n3
C7n
1n
C6Br
23.4
24.1
24.6
24.7
25.2
22.3
Sr-isotope
ages (Ma)
Hole 904A
-0.02 0.02
reflection m6
0
Miller et al., Science, Fig. S5
300
304
316
320
Depth (mbsf) (Site 904A)
Age (Ma) (Site 929 only)
Hole 904A
vs. depth
Mi1
12 0
benthic
Site 929,
plotted
vs. age
δ
18
O
26
22
23
24
25
photographs
Cores 33 and 34
308
312
150